Emailing eBay is not recommended. Emails are useless, for a number of reasons, but primarily because the responses, when they are finally sent, are bot-generated.
You can get in touch with eBay via Live Chat, but you really haven't provided enough information for us to be able to recommend that this is the best way to resolve your issue.
Has your credit card been hacked? Is it a case of a transaction you don't recognise appearing in your account?
Or is it a case of a transaction amount being taken out twice?
Or ... etc.
If you can clarify, the responders here will be able to give better advice - but yes, very definitely, if you have the SLIGHTEST suspicion that your card has been compromised, call your bank immediately.
